Plumbing and heating plan thoughts?

[DIWye]

Been a bit slower with the plumbing than I'd like but better late than never... I'd like to get your thoughts on my plumbing plan below for the reno (accidentally missed off the outside tap that tees of the 25mm MDPE):

 

Does this seems like a reasonable plan for the cold and DHW feeds? Is it worth running 22mm hot to the bathroom for the bath/over bath shower? I think I've made a bit of an error with the ensuite (far left on diagram), I've fitted this already but realised I probably should have ran a separate feed for the electric shower, hoping it doesn't affect the pressure too much.

 

Anything I should be thinking about with double check vales/pressure reducing valves etc? Or any recommendations for sources I can read up on this kind of stuff? 

 

There's no central heating in the house, but we've got access to an oil combi that we are planning on installing in the next month or so. I was thinking of a setup along the lines of that shown below for the heating (I've added approx pipe run length from the boiler) Running 22mm until I get to the rough area, and then branching to 15mm for the rads. I've read that you should only have 3 rads coming off a 22mm pipe, so I may be pushing it a bit here? Does anyone have any experience of running UFH with a combi boiler, anything to consider with this?

 

 

Any critique/thoughts would be greatly appreciated! Cheers

[JohnMo]

Do all your hot and cold in no bigger than 15mm, otherwise you will waiting for ever and a day for hot water. 

 

You don't need separate feeds, unlikely to use all three colds in the ensuite at the same time.

 

 

[joe90]

I ran hot and cold feeds to basins and toilets in 10mm, hot water got there faster and pressure/flow is fine (not kitchen tap).

[DIWye]

Nice one, thanks both for confirming.

 

The old water feed to the house that I've T'd off is a black alkathene pipe, just under 22mm OD and about 14mm ID, which I think makes it a half inch class D pipe. Any ideas for a suitable insert for using a compression fitting to get it to the 25mm MDPE? I was hoping Screwfix's 20mm pipe liners might do it but no joy... Been using one of these (https://www.screwfix.com/p/floplast-492113-mdpe-reducing-coupler-25mm-x-20mm/14632?ref=SFAppShare) to try and get from the alkathene to 25mm MDPE, which I thought worked but there is a tiny leak, hoping that a suitable pipe insert on the alkathene will sort that

[Eric]

Black pipe will be imperial, you will need an imperial to mdpe coupler.